The invention relates to an apparatus for managing a local area network, in particular, it relates to a switching mechanism that is used to manage the physical layer of a local area network.
Local area networks (LANs) provide a popular, cost effective way of interconnecting many computing resources (e.g. personal computers, minicomputers or workstations) within an enterprise. The backbone of the LAN is a wiring system that provides a physical transmission medium for interconnecting the computing resources. The wiring system may be coaxial cable, shielded or unshielded copper wire, or fiber optic cable. For each computing resource there is a transceiver that provides the electrical connection or interface between the computing resource and the wiring system. The transceiver converts the information from the computing resource into the actual signals that propagate over the wiring system. The LAN also includes network software which assembles the messages into the format required by the particular protocol used for communication over the network.
A common LAN configuration is the ring network. It is so named because the computing resources or stations are connected together through a series of point-to-point cables to form a ring. Such ring networks are thus inherently ordered, each station having an upstream neighbor from which it receives information and a downstream neighbor to which it transfers information. In one of the oldest and most commonly used ring networks, a bit pattern, referred to as a token, circulates around the ring from one station to the next. When a station has something to send to another station, it captures the token and gains the right to transmit information over the network. When its transmission is complete, it releases the token so that some other station can gain the right to transmit over the network.
Typically, the actual physical interconnections in the ring network occur at one or more central locations referred to as wiring closets. For each station in the ring, cables are run into the wiring closet that carry communications to and from that station. In such systems, when reconfiguring the ring becomes necessary for any reason (e.g. for maintenance and repair or changing needs of the network users), it is necessary to go into the wiring closets and manually rewire the interconnections. This, of course, can be a time consuming and difficult job. In addition, physically disturbing the cables and the interconnections increases the risk that network failures will occur.